The present invention relates to refuse handling methods and apparatus, and more particularly, to refuse collection vehicles and methods for compacting refuse inside the same.
Refuse collection vehicles are widely used throughout the United States for picking up refuse from residences and businesses and dumping the refuse at landfills. Typically they comprise a truck chassis with a large hollow steel refuse storage body into which refuse is densely compacted. Two popular configurations for refuse collection vehicles are the front loader and the side loader. The front loader lifts a large steel refuse bin over the driver's cab with pivoting forks that invert the bin and pour its contents into a forward hopper section of the refuse storage body. The side loader has a pivoting lift arm that is extensible from the side of the vehicle to grip a plastic garbage can from a curbside, lift it upwardly along the arm, and invert the can to pour its contents into the hopper section.
Refuse collection vehicles of the foregoing type have a compactor mechanism for pushing refuse received into the hopper section rearwardly. Usually this mechanism takes the form of a single so-called packer blade which is reciprocated rearwardly and forwardly by a hydraulic cylinder to push refuse emptied into the hopper section into a rear section of the refuse storage body. Once the body has been filled with compacted refuse, the vehicle is driven to a land fill. The forward end of the refuse storage body is then lifted upwardly from the vehicle chassis to pivot the body and its rearward tailgate is opened so that the compacted refuse slides by gravity out of the body and onto the ground. See U.S. Pat. No. 4,552,500 of Ghibaudo et al.
The refuse collection vehicle can become dangerously unstable if the body is tilted too far and/or the vehicle is on too much of an incline when the body is tilted. Therefore, it has become popular to use a very long multi-stage hydraulic cylinder which can push the packer blade substantially the entire length of the refuse storage body to eject the refuse out the open rear end of the body without having to tilt the body on the vehicle chassis. However, such multi-stage hydraulic cylinders require substantial maintenance and are expensive to replace. Typically they must cycle thousands of times a day over short compacting strokes, while only having to travel a full stroke to eject a full body of refuse less than a dozen times per day, once for each trip to a landfill. Also, this packer arrangement suffers from springback of the refuse from the rear section of the body into the hopper section when the packer blade returns to its forward-most position.